1 use crate::reexport::*;
2 use if_chain::if_chain;
5 use rustc::hir::def::Def;
6 use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
7 use rustc::hir::intravisit::{NestedVisitorMap, Visitor};
10 use rustc::lint::{LateContext, Level, Lint, LintContext};
11 use rustc::session::Session;
15 layout::{self, IntegerExt},
19 use rustc_data_structures::sync::Lrc;
20 use rustc_errors::{Applicability, CodeSuggestion, Substitution, SubstitutionPart};
24 use std::str::FromStr;
25 use syntax::ast::{self, LitKind};
27 use syntax::errors::DiagnosticBuilder;
28 use syntax::source_map::{Span, DUMMY_SP};
30 use syntax::symbol::{keywords, Symbol};
40 pub mod internal_lints;
45 pub use self::hir_utils::{SpanlessEq, SpanlessHash};
49 /// Returns true if the two spans come from differing expansions (i.e. one is
50 /// from a macro and one
52 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
53 rhs.ctxt() != lhs.ctxt()
56 /// Returns `true` if the given `NodeId` is inside a constant context
61 /// if in_constant(cx, expr.id) {
65 pub fn in_constant(cx: &LateContext<'_, '_>, id: NodeId) -> bool {
66 let parent_id = cx.tcx.hir().get_parent(id);
67 match cx.tcx.hir().get(parent_id) {
69 node: ItemKind::Const(..),
72 | Node::TraitItem(&TraitItem {
73 node: TraitItemKind::Const(..),
76 | Node::ImplItem(&ImplItem {
77 node: ImplItemKind::Const(..),
82 node: ItemKind::Static(..),
86 node: ItemKind::Fn(_, header, ..),
88 }) => header.constness == Constness::Const,
93 /// Returns true if this `expn_info` was expanded by any macro.
94 pub fn in_macro(span: Span) -> bool {
95 span.ctxt().outer().expn_info().is_some()
98 /// Used to store the absolute path to a type.
100 /// See `match_def_path` for usage.
102 pub struct AbsolutePathBuffer {
103 pub names: Vec<symbol::LocalInternedString>,
106 impl ty::item_path::ItemPathBuffer for AbsolutePathBuffer {
107 fn root_mode(&self) -> &ty::item_path::RootMode {
108 const ABSOLUTE: &ty::item_path::RootMode = &ty::item_path::RootMode::Absolute;
112 fn push(&mut self, text: &str) {
113 self.names.push(symbol::Symbol::intern(text).as_str());
117 /// Check if a `DefId`'s path matches the given absolute type path usage.
121 /// match_def_path(cx.tcx, id, &["core", "option", "Option"])
124 /// See also the `paths` module.
125 pub fn match_def_path(tcx: TyCtxt<'_, '_, '_>, def_id: DefId, path: &[&str]) -> bool {
126 let mut apb = AbsolutePathBuffer { names: vec![] };
128 tcx.push_item_path(&mut apb, def_id, false);
130 apb.names.len() == path.len() && apb.names.into_iter().zip(path.iter()).all(|(a, &b)| *a == *b)
133 pub fn get_def_path(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Vec<&'static str> {
134 let mut apb = AbsolutePathBuffer { names: vec![] };
135 tcx.push_item_path(&mut apb, def_id, false);
136 apb.names.iter().map(|n| n.get()).collect()
139 /// Check if type is struct, enum or union type with given def path.
140 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[&str]) -> bool {
142 ty::Adt(adt, _) => match_def_path(cx.tcx, adt.did, path),
147 /// Check if the method call given in `expr` belongs to given trait.
148 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[&str]) -> bool {
149 let method_call = cx.tables.type_dependent_defs()[expr.hir_id];
150 let trt_id = cx.tcx.trait_of_item(method_call.def_id());
151 if let Some(trt_id) = trt_id {
152 match_def_path(cx.tcx, trt_id, path)
158 /// Check if an expression references a variable of the given name.
159 pub fn match_var(expr: &Expr, var: Name) -> bool {
160 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
161 if path.segments.len() == 1 && path.segments[0].ident.name == var {
168 pub fn last_path_segment(path: &QPath) -> &PathSegment {
170 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
171 QPath::TypeRelative(_, ref seg) => seg,
175 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
177 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
178 QPath::Resolved(..) => None,
179 QPath::TypeRelative(_, ref seg) => Some(seg),
183 /// Match a `Path` against a slice of segment string literals.
187 /// match_qpath(path, &["std", "rt", "begin_unwind"])
189 pub fn match_qpath(path: &QPath, segments: &[&str]) -> bool {
191 QPath::Resolved(_, ref path) => match_path(path, segments),
192 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
193 TyKind::Path(ref inner_path) => {
195 && match_qpath(inner_path, &segments[..(segments.len() - 1)])
196 && segment.ident.name == segments[segments.len() - 1]
203 pub fn match_path(path: &Path, segments: &[&str]) -> bool {
207 .zip(segments.iter().rev())
208 .all(|(a, b)| a.ident.name == *b)
211 /// Match a `Path` against a slice of segment string literals, e.g.
215 /// match_qpath(path, &["std", "rt", "begin_unwind"])
217 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
221 .zip(segments.iter().rev())
222 .all(|(a, b)| a.ident.name == *b)
225 /// Get the definition associated to a path.
226 pub fn path_to_def(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<def::Def> {
227 let crates = cx.tcx.crates();
228 let krate = crates.iter().find(|&&krate| cx.tcx.crate_name(krate) == path[0]);
229 if let Some(krate) = krate {
232 index: CRATE_DEF_INDEX,
234 let mut items = cx.tcx.item_children(krate);
235 let mut path_it = path.iter().skip(1).peekable();
238 let segment = match path_it.next() {
239 Some(segment) => segment,
243 for item in mem::replace(&mut items, Lrc::new(vec![])).iter() {
244 if item.ident.name == *segment {
245 if path_it.peek().is_none() {
246 return Some(item.def);
249 items = cx.tcx.item_children(item.def.def_id());
259 /// Convenience function to get the `DefId` of a trait by path.
260 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
261 let def = match path_to_def(cx, path) {
267 def::Def::Trait(trait_id) => Some(trait_id),
272 /// Check whether a type implements a trait.
273 /// See also `get_trait_def_id`.
274 pub fn implements_trait<'a, 'tcx>(
275 cx: &LateContext<'a, 'tcx>,
278 ty_params: &[Kind<'tcx>],
280 let ty = cx.tcx.erase_regions(&ty);
281 let obligation = cx.tcx.predicate_for_trait_def(
283 traits::ObligationCause::dummy(),
291 .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
294 /// Check whether this type implements Drop.
295 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
296 match ty.ty_adt_def() {
297 Some(def) => def.has_dtor(cx.tcx),
302 /// Resolve the definition of a node from its `HirId`.
303 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> def::Def {
304 cx.tables.qpath_def(qpath, id)
307 /// Return the method names and argument list of nested method call expressions that make up
309 pub fn method_calls<'a>(expr: &'a Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&'a [Expr]>) {
310 let mut method_names = Vec::with_capacity(max_depth);
311 let mut arg_lists = Vec::with_capacity(max_depth);
313 let mut current = expr;
314 for _ in 0..max_depth {
315 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
316 if args.iter().any(|e| in_macro(e.span)) {
319 method_names.push(path.ident.name);
320 arg_lists.push(&**args);
327 (method_names, arg_lists)
330 /// Match an `Expr` against a chain of methods, and return the matched `Expr`s.
332 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
333 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
334 /// containing the `Expr`s for
335 /// `.bar()` and `.baz()`
336 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
337 let mut current = expr;
338 let mut matched = Vec::with_capacity(methods.len());
339 for method_name in methods.iter().rev() {
340 // method chains are stored last -> first
341 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
342 if path.ident.name == *method_name {
343 if args.iter().any(|e| in_macro(e.span)) {
346 matched.push(&**args); // build up `matched` backwards
347 current = &args[0] // go to parent expression
355 matched.reverse(); // reverse `matched`, so that it is in the same order as `methods`
359 /// Returns true if the provided `def_id` is an entrypoint to a program
360 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
361 if let Some((entry_fn_def_id, _)) = cx.tcx.entry_fn(LOCAL_CRATE) {
362 return def_id == entry_fn_def_id;
367 /// Get the name of the item the expression is in, if available.
368 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
369 let parent_id = cx.tcx.hir().get_parent(expr.id);
370 match cx.tcx.hir().find(parent_id) {
371 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
372 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
379 /// Get the name of a `Pat`, if any
380 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
382 PatKind::Binding(_, _, ref spname, _) => Some(spname.name),
383 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
384 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
389 struct ContainsName {
394 impl<'tcx> Visitor<'tcx> for ContainsName {
395 fn visit_name(&mut self, _: Span, name: Name) {
396 if self.name == name {
400 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
401 NestedVisitorMap::None
405 /// check if an `Expr` contains a certain name
406 pub fn contains_name(name: Name, expr: &Expr) -> bool {
407 let mut cn = ContainsName { name, result: false };
412 /// Convert a span to a code snippet if available, otherwise use default.
414 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
415 /// to convert a given `Span` to a `str`.
419 /// snippet(cx, expr.span, "..")
421 pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
422 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
425 /// Same as `snippet`, but it adapts the applicability level by following rules:
427 /// - Applicability level `Unspecified` will never be changed.
428 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
429 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
430 /// `HasPlaceholders`
431 pub fn snippet_with_applicability<'a, 'b, T: LintContext<'b>>(
435 applicability: &mut Applicability,
437 if *applicability != Applicability::Unspecified && in_macro(span) {
438 *applicability = Applicability::MaybeIncorrect;
440 snippet_opt(cx, span).map_or_else(
442 if *applicability == Applicability::MachineApplicable {
443 *applicability = Applicability::HasPlaceholders;
445 Cow::Borrowed(default)
451 /// Same as `snippet`, but should only be used when it's clear that the input span is
452 /// not a macro argument.
453 pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
454 snippet(cx, span.source_callsite(), default)
457 /// Convert a span to a code snippet. Returns `None` if not available.
458 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
459 cx.sess().source_map().span_to_snippet(span).ok()
462 /// Convert a span (from a block) to a code snippet if available, otherwise use
464 /// This trims the code of indentation, except for the first line. Use it for
465 /// blocks or block-like
466 /// things which need to be printed as such.
470 /// snippet_block(cx, expr.span, "..")
472 pub fn snippet_block<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
473 let snip = snippet(cx, span, default);
474 trim_multiline(snip, true)
477 /// Same as `snippet_block`, but adapts the applicability level by the rules of
478 /// `snippet_with_applicabiliy`.
479 pub fn snippet_block_with_applicability<'a, 'b, T: LintContext<'b>>(
483 applicability: &mut Applicability,
485 let snip = snippet_with_applicability(cx, span, default, applicability);
486 trim_multiline(snip, true)
489 /// Returns a new Span that covers the full last line of the given Span
490 pub fn last_line_of_span<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Span {
491 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
492 let line_no = source_map_and_line.line;
493 let line_start = &source_map_and_line.sf.lines[line_no];
494 Span::new(*line_start, span.hi(), span.ctxt())
497 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
498 /// Also takes an `Option<String>` which can be put inside the braces.
499 pub fn expr_block<'a, 'b, T: LintContext<'b>>(
502 option: Option<String>,
505 let code = snippet_block(cx, expr.span, default);
506 let string = option.unwrap_or_default();
507 if in_macro(expr.span) {
508 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
509 } else if let ExprKind::Block(_, _) = expr.node {
510 Cow::Owned(format!("{}{}", code, string))
511 } else if string.is_empty() {
512 Cow::Owned(format!("{{ {} }}", code))
514 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
518 /// Trim indentation from a multiline string with possibility of ignoring the
520 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
521 let s_space = trim_multiline_inner(s, ignore_first, ' ');
522 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
523 trim_multiline_inner(s_tab, ignore_first, ' ')
526 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
529 .skip(ignore_first as usize)
534 // ignore empty lines
535 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
545 if (ignore_first && i == 0) || l.is_empty() {
559 /// Get a parent expressions if any – this is useful to constrain a lint.
560 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
561 let map = &cx.tcx.hir();
562 let node_id: NodeId = e.id;
563 let parent_id: NodeId = map.get_parent_node(node_id);
564 if node_id == parent_id {
567 map.find(parent_id).and_then(|node| {
568 if let Node::Expr(parent) = node {
576 pub fn get_enclosing_block<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, node: NodeId) -> Option<&'tcx Block> {
577 let map = &cx.tcx.hir();
578 let enclosing_node = map
579 .get_enclosing_scope(node)
580 .and_then(|enclosing_id| map.find(enclosing_id));
581 if let Some(node) = enclosing_node {
583 Node::Block(block) => Some(block),
585 node: ItemKind::Fn(_, _, _, eid),
588 | Node::ImplItem(&ImplItem {
589 node: ImplItemKind::Method(_, eid),
591 }) => match cx.tcx.hir().body(eid).value.node {
592 ExprKind::Block(ref block, _) => Some(block),
602 pub struct DiagnosticWrapper<'a>(pub DiagnosticBuilder<'a>);
604 impl<'a> Drop for DiagnosticWrapper<'a> {
610 impl<'a> DiagnosticWrapper<'a> {
611 fn docs_link(&mut self, lint: &'static Lint) {
612 if env::var("CLIPPY_DISABLE_DOCS_LINKS").is_err() {
613 self.0.help(&format!(
614 "for further information visit https://rust-lang.github.io/rust-clippy/{}/index.html#{}",
615 &option_env!("RUST_RELEASE_NUM").map_or("master".to_string(), |n| {
616 // extract just major + minor version and ignore patch versions
617 format!("rust-{}", n.rsplitn(2, '.').nth(1).unwrap())
619 lint.name_lower().replacen("clippy::", "", 1)
625 pub fn span_lint<'a, T: LintContext<'a>>(cx: &T, lint: &'static Lint, sp: Span, msg: &str) {
626 DiagnosticWrapper(cx.struct_span_lint(lint, sp, msg)).docs_link(lint);
629 pub fn span_help_and_lint<'a, 'tcx: 'a, T: LintContext<'tcx>>(
636 let mut db = DiagnosticWrapper(cx.struct_span_lint(lint, span, msg));
641 pub fn span_note_and_lint<'a, 'tcx: 'a, T: LintContext<'tcx>>(
649 let mut db = DiagnosticWrapper(cx.struct_span_lint(lint, span, msg));
650 if note_span == span {
653 db.0.span_note(note_span, note);
658 pub fn span_lint_and_then<'a, 'tcx: 'a, T: LintContext<'tcx>, F>(
665 F: for<'b> FnOnce(&mut DiagnosticBuilder<'b>),
667 let mut db = DiagnosticWrapper(cx.struct_span_lint(lint, sp, msg));
672 pub fn span_lint_node(cx: &LateContext<'_, '_>, lint: &'static Lint, node: NodeId, sp: Span, msg: &str) {
673 DiagnosticWrapper(cx.tcx.struct_span_lint_node(lint, node, sp, msg)).docs_link(lint);
676 pub fn span_lint_node_and_then(
677 cx: &LateContext<'_, '_>,
682 f: impl FnOnce(&mut DiagnosticBuilder<'_>),
684 let mut db = DiagnosticWrapper(cx.tcx.struct_span_lint_node(lint, node, sp, msg));
689 /// Add a span lint with a suggestion on how to fix it.
691 /// These suggestions can be parsed by rustfix to allow it to automatically fix your code.
692 /// In the example below, `help` is `"try"` and `sugg` is the suggested replacement `".any(|x| x >
696 /// error: This `.fold` can be more succinctly expressed as `.any`
697 /// --> $DIR/methods.rs:390:13
699 /// 390 | let _ = (0..3).fold(false, |acc, x| acc || x > 2);
700 /// | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `.any(|x| x > 2)`
702 /// = note: `-D fold-any` implied by `-D warnings`
704 pub fn span_lint_and_sugg<'a, 'tcx: 'a, T: LintContext<'tcx>>(
711 applicability: Applicability,
713 span_lint_and_then(cx, lint, sp, msg, |db| {
714 db.span_suggestion(sp, help, sugg, applicability);
718 /// Create a suggestion made from several `span → replacement`.
720 /// Note: in the JSON format (used by `compiletest_rs`), the help message will
722 /// replacement. In human-readable format though, it only appears once before
723 /// the whole suggestion.
724 pub fn multispan_sugg<I>(db: &mut DiagnosticBuilder<'_>, help_msg: String, sugg: I)
726 I: IntoIterator<Item = (Span, String)>,
728 let sugg = CodeSuggestion {
729 substitutions: vec![Substitution {
732 .map(|(span, snippet)| SubstitutionPart { snippet, span })
736 show_code_when_inline: true,
737 applicability: Applicability::Unspecified,
739 db.suggestions.push(sugg);
742 /// Return the base type for HIR references and pointers.
743 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
745 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
750 /// Return the base type for references and raw pointers.
751 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
753 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
758 /// Return the base type for references and raw pointers, and count reference
760 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
761 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
763 ty::Ref(_, ty, _) => inner(ty, depth + 1),
770 /// Check whether the given expression is a constant literal of the given value.
771 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
772 // FIXME: use constant folding
773 if let ExprKind::Lit(ref spanned) = expr.node {
774 if let LitKind::Int(v, _) = spanned.node {
781 /// Returns `true` if the given `Expr` has been coerced before.
783 /// Examples of coercions can be found in the Nomicon at
784 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
786 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
787 /// information on adjustments and coercions.
788 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
789 cx.tables.adjustments().get(e.hir_id).is_some()
792 pub struct LimitStack {
796 impl Drop for LimitStack {
798 assert_eq!(self.stack.len(), 1);
803 pub fn new(limit: u64) -> Self {
804 Self { stack: vec![limit] }
806 pub fn limit(&self) -> u64 {
807 *self.stack.last().expect("there should always be a value in the stack")
809 pub fn push_attrs(&mut self, sess: &Session, attrs: &[ast::Attribute], name: &'static str) {
810 let stack = &mut self.stack;
811 parse_attrs(sess, attrs, name, |val| stack.push(val));
813 pub fn pop_attrs(&mut self, sess: &Session, attrs: &[ast::Attribute], name: &'static str) {
814 let stack = &mut self.stack;
815 parse_attrs(sess, attrs, name, |val| assert_eq!(stack.pop(), Some(val)));
819 pub fn get_attr<'a>(attrs: &'a [ast::Attribute], name: &'static str) -> impl Iterator<Item = &'a ast::Attribute> {
820 attrs.iter().filter(move |attr| {
821 attr.path.segments.len() == 2
822 && attr.path.segments[0].ident.to_string() == "clippy"
823 && attr.path.segments[1].ident.to_string() == name
827 fn parse_attrs<F: FnMut(u64)>(sess: &Session, attrs: &[ast::Attribute], name: &'static str, mut f: F) {
828 for attr in get_attr(attrs, name) {
829 if let Some(ref value) = attr.value_str() {
830 if let Ok(value) = FromStr::from_str(&value.as_str()) {
833 sess.span_err(attr.span, "not a number");
836 sess.span_err(attr.span, "bad clippy attribute");
841 /// Return the pre-expansion span if is this comes from an expansion of the
843 /// See also `is_direct_expn_of`.
844 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
846 let span_name_span = span
850 .map(|ei| (ei.format.name(), ei.call_site));
852 match span_name_span {
853 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
855 Some((_, new_span)) => span = new_span,
860 /// Return the pre-expansion span if is this directly comes from an expansion
861 /// of the macro `name`.
862 /// The difference with `is_expn_of` is that in
866 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
868 /// `is_direct_expn_of`.
869 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
870 let span_name_span = span
874 .map(|ei| (ei.format.name(), ei.call_site));
876 match span_name_span {
877 Some((mac_name, new_span)) if mac_name == name => Some(new_span),
882 /// Convenience function to get the return type of a function
883 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: NodeId) -> Ty<'tcx> {
884 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
885 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
886 cx.tcx.erase_late_bound_regions(&ret_ty)
889 /// Check if two types are the same.
891 /// This discards any lifetime annotations, too.
892 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` == `for
894 // not for type parameters.
895 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
896 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
897 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
900 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
903 /// Return whether the given type is an `unsafe` function.
904 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
906 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
911 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
912 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
915 /// Return whether a pattern is refutable.
916 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
917 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
919 cx.tables.qpath_def(qpath, id),
920 def::Def::Variant(..) | def::Def::VariantCtor(..)
924 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
925 i.any(|pat| is_refutable(cx, pat))
929 PatKind::Binding(..) | PatKind::Wild => false,
930 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
931 PatKind::Lit(..) | PatKind::Range(..) => true,
932 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
933 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
934 PatKind::Struct(ref qpath, ref fields, _) => {
935 if is_enum_variant(cx, qpath, pat.hir_id) {
938 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
941 PatKind::TupleStruct(ref qpath, ref pats, _) => {
942 if is_enum_variant(cx, qpath, pat.hir_id) {
945 are_refutable(cx, pats.iter().map(|pat| &**pat))
948 PatKind::Slice(ref head, ref middle, ref tail) => {
949 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
954 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
955 /// implementations have.
956 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
957 attr::contains_name(attrs, "automatically_derived")
960 /// Remove blocks around an expression.
962 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
964 pub fn remove_blocks(expr: &Expr) -> &Expr {
965 if let ExprKind::Block(ref block, _) = expr.node {
966 if block.stmts.is_empty() {
967 if let Some(ref expr) = block.expr {
980 pub fn opt_def_id(def: Def) -> Option<DefId> {
986 | Def::VariantCtor(id, ..)
989 | Def::AssociatedTy(id)
993 | Def::StructCtor(id, ..)
996 | Def::TraitAlias(id)
999 | Def::AssociatedConst(id)
1000 | Def::Macro(id, ..)
1001 | Def::Existential(id)
1002 | Def::AssociatedExistential(id)
1003 | Def::SelfCtor(id) => Some(id),
1011 | Def::NonMacroAttr { .. }
1016 pub fn is_self(slf: &Arg) -> bool {
1017 if let PatKind::Binding(_, _, name, _) = slf.pat.node {
1018 name.name == keywords::SelfLower.name()
1024 pub fn is_self_ty(slf: &hir::Ty) -> bool {
1026 if let TyKind::Path(ref qp) = slf.node;
1027 if let QPath::Resolved(None, ref path) = *qp;
1028 if let Def::SelfTy(..) = path.def;
1036 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
1037 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
1040 /// Check if a given expression is a match expression
1041 /// expanded from `?` operator or `try` macro.
1042 pub fn is_try(expr: &Expr) -> Option<&Expr> {
1043 fn is_ok(arm: &Arm) -> bool {
1045 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
1046 if match_qpath(path, &paths::RESULT_OK[1..]);
1047 if let PatKind::Binding(_, defid, _, None) = pat[0].node;
1048 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
1049 if let Def::Local(lid) = path.def;
1058 fn is_err(arm: &Arm) -> bool {
1059 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
1060 match_qpath(path, &paths::RESULT_ERR[1..])
1066 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
1067 // desugared from a `?` operator
1068 if let MatchSource::TryDesugar = *source {
1074 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
1075 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
1076 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
1077 (is_ok(&arms[1]) && is_err(&arms[0]));
1087 /// Returns true if the lint is allowed in the current context
1089 /// Useful for skipping long running code when it's unnecessary
1090 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: NodeId) -> bool {
1091 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1094 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
1096 PatKind::Binding(_, _, ident, None) => Some(ident.name),
1097 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
1102 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
1103 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
1108 #[allow(clippy::cast_possible_wrap)]
1109 /// Turn a constant int byte representation into an i128
1110 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
1111 let amt = 128 - int_bits(tcx, ity);
1112 ((u as i128) << amt) >> amt
1115 #[allow(clippy::cast_sign_loss)]
1116 /// clip unused bytes
1117 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
1118 let amt = 128 - int_bits(tcx, ity);
1119 ((u as u128) << amt) >> amt
1122 /// clip unused bytes
1123 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
1124 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
1127 let amt = 128 - bits;
1131 /// Remove block comments from the given Vec of lines
1136 /// without_block_comments(vec!["/*", "foo", "*/"]);
1139 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
1140 /// // => vec!["bar"]
1142 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
1143 let mut without = vec![];
1145 let mut nest_level = 0;
1148 if line.contains("/*") {
1151 } else if line.contains("*/") {
1156 if nest_level == 0 {
1164 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: NodeId) -> bool {
1165 let map = &tcx.hir();
1166 let mut prev_enclosing_node = None;
1167 let mut enclosing_node = node;
1168 while Some(enclosing_node) != prev_enclosing_node {
1169 if is_automatically_derived(map.attrs(enclosing_node)) {
1172 prev_enclosing_node = Some(enclosing_node);
1173 enclosing_node = map.get_parent(enclosing_node);
1180 use super::{trim_multiline, without_block_comments};
1183 fn test_trim_multiline_single_line() {
1184 assert_eq!("", trim_multiline("".into(), false));
1185 assert_eq!("...", trim_multiline("...".into(), false));
1186 assert_eq!("...", trim_multiline(" ...".into(), false));
1187 assert_eq!("...", trim_multiline("\t...".into(), false));
1188 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1193 fn test_trim_multiline_block() {
1199 }", trim_multiline(" if x {
1209 }", trim_multiline(" if x {
1218 fn test_trim_multiline_empty_line() {
1225 }", trim_multiline(" if x {
1234 fn test_without_block_comments_lines_without_block_comments() {
1235 let result = without_block_comments(vec!["/*", "", "*/"]);
1236 println!("result: {:?}", result);
1237 assert!(result.is_empty());
1239 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1240 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1242 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1243 assert!(result.is_empty());
1245 let result = without_block_comments(vec!["/* one-line comment */"]);
1246 assert!(result.is_empty());
1248 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1249 assert!(result.is_empty());
1251 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1252 assert!(result.is_empty());
1254 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1255 assert_eq!(result, vec!["foo", "bar", "baz"]);